Ranking municipal solid waste treatment alternatives based on ecological footprint and multi-criteria analysis

The selection of a municipal solid waste (MSW) treatment alternative is a complex task in which a widespread set of criteria must be taken into account. Additionally to economic or social aspects, the decision process should consider the environmental perspective. With the purpose of quantifying the environmental burdens, a wide variety of environmental and sustainability indicators have been developed in the last years. Furthermore, integrative frameworks have been highlighted as the best option to achieve more comprehensive assessments. In this work, four different options of MSW treatment were ranked from an environmental point of view applying two methods: (1) the ecological footprint (EF) as single composite indicator and (2) multi-criteria analysis (MCA) integrating the EF together with other material flow indicators related to water consumption, emissions to air and water and occupied landfill volume. The MCA methods selected were a combination of Analytic Hierarchy Process (AHP) and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) aided by Geometrical Analysis for Interactive Aid (GAIA). The objective was twofold: on the one side, the identification of the most beneficial waste treatment alternative (including thermal plasma gasification which as yet has not been assessed systematically) from an environmental perspective and, on the other side, the comparison of the results yielded by the two ranking methods proposed. The ranking obtained in both cases was (from best to worst): thermal plasma gasification, biological treatment of organic fraction with energy recovery from refuse derived fuel, incineration with energy recovery and landfilling. Hence, the EF proved to be a good screening indicator although it did not provide a comprehensive measure of environmental impacts associated to the waste treatment options considered. Besides, the combined application of AHP and PROMETHEE/GAIA as MCA methodology was found to be a suitable way, not very complex at user level, to integrate the information provided by a set of environmental criteria and to aid decision making. (c) 2012 Elsevier Ltd. All rights reserved.